454 difference
07-23-2006, 11:09 PM
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454 difference
Whats the difference between an 88' 454 (330 h.p.) to a 85' 400 trs(400 h.p.).? I'm thinging about keeping my 454 330 as a spare to the 400 trs but need to know what upgrades I need to make them equal. Thanks
07-24-2006, 05:53 AM
#2
Re: 454 difference
Prostock,
Do a search on Merc 330hp upgrades within the forum---there is a BUNCH of info about the subject.
The Merc 400hp engine has ALL forged parts (pistons, 7/16" rods, cranks) and a 4-bolt main block, rectangle port heads with 2.19" intake valves and 1.88" exhaust valves, dual plane aluminum hi-rise intake manifold, cast aluminum valve covers, Crane gold aluminum roller rocker arms, and a larger flat tappet hydraulic camshaft.
Somewhere right around the late 1980's the Merc 330hp engine has had some changes internally with it components, but I cannot remember exactly what they are---I am sure someone else will know and chime in here. The Merc 330hp engine the way I knew them BEFORE the changes had cast pistons, 3/8" rods which is NOT a truely forged rod, cast crank, 2-bolt main block, oval port heads with 2.06" intake valves and 1.72" exhaust valves, flat pancake style cast iron intake manifold, stamped steel stock rocker arms, and a small hydraulic flat tappet camshaft.
It will be pretty easy to get 400hp out of a 454cid marine engine that was once a Merc 330, but everything should start out with a good block meaning properly measured and precision machined from a reputable/competent machine shop familiar with building marine engines. This should include an align hone on the main saddles of the block. You will at least need some forged pistons, shot peen the rods, recondition, and install new ARP rod bolts, a cast crank will be fine around 5500rpm or so unless you definately want a forged crank. Have the oval port heads bowl/pocket ported (if you're only looking for 400hp you probably WON'T need larger valves installed), a good valve job, a good dual plane aluminum aftermarket intake manifold, and a larger hydraulic camshaft----these days the better option is to go with a hydraulic ROLLER camshaft vs a flat tappet, the roller is more reliable and will give you more power, but MUCH more expensive, but it's not or may not be totally necessary for 400hp. The flat tappet cam and lifters are much cheaper, but they must be properly installed and broke-in properly.
Do a search on Merc 330hp upgrades within the forum---there is a BUNCH of info about the subject.
The Merc 400hp engine has ALL forged parts (pistons, 7/16" rods, cranks) and a 4-bolt main block, rectangle port heads with 2.19" intake valves and 1.88" exhaust valves, dual plane aluminum hi-rise intake manifold, cast aluminum valve covers, Crane gold aluminum roller rocker arms, and a larger flat tappet hydraulic camshaft.
Somewhere right around the late 1980's the Merc 330hp engine has had some changes internally with it components, but I cannot remember exactly what they are---I am sure someone else will know and chime in here. The Merc 330hp engine the way I knew them BEFORE the changes had cast pistons, 3/8" rods which is NOT a truely forged rod, cast crank, 2-bolt main block, oval port heads with 2.06" intake valves and 1.72" exhaust valves, flat pancake style cast iron intake manifold, stamped steel stock rocker arms, and a small hydraulic flat tappet camshaft.
It will be pretty easy to get 400hp out of a 454cid marine engine that was once a Merc 330, but everything should start out with a good block meaning properly measured and precision machined from a reputable/competent machine shop familiar with building marine engines. This should include an align hone on the main saddles of the block. You will at least need some forged pistons, shot peen the rods, recondition, and install new ARP rod bolts, a cast crank will be fine around 5500rpm or so unless you definately want a forged crank. Have the oval port heads bowl/pocket ported (if you're only looking for 400hp you probably WON'T need larger valves installed), a good valve job, a good dual plane aluminum aftermarket intake manifold, and a larger hydraulic camshaft----these days the better option is to go with a hydraulic ROLLER camshaft vs a flat tappet, the roller is more reliable and will give you more power, but MUCH more expensive, but it's not or may not be totally necessary for 400hp. The flat tappet cam and lifters are much cheaper, but they must be properly installed and broke-in properly.
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